(i) Field of the Invention
This invention relates generally to improved geotextiles for building longer lasting roads. More particularly, it relates to a novel type of fabric in which high bulk yarn is interwoven with tape; its use in building roads; and the improved road thereby obtained.
(ii) Description of the Prior Art
The term "geotextile" is of very recent origin. It is typically used to describe a fabric designed for use in or on the ground in civil engineering and construction applications to promote durability. In general, such durability is obtained by the geotextile functioning as (i) reinforcement and load distributor; and/or (ii) a permeable membrane that permits passage of liquids; and/or (iii) a confiner that prevents erosion or a separator that prevents intermingling of different granular masses on each side of the fabric.
Numerous different geotextiles have been used in repairing a cracked load bearing surface, such as a road pavement by steps including: (a) filling the cracks with bituminous or elastomeric material; (b) applying an asphalt tack coat to the filled surface; (c) laying a geotextile on top of the tack coat; and (d) applying and compacting hot asphalt concrete on top of the geotextile.
Procedures for bonding the fabric are well known in the art. For example, see "PM-13 Mirafi.RTM. 140 Fabric for Longer Lasting Pavement Overlay" by Celanese Fibers Marketing Company, 1978.
A detailed description of the prior art relating to geotextiles, particularly woven fabrics, for building longer lasting roads is found at the beginning of U.S. patent application Ser. No. 160,264 ("Geotextile for Pavement Overlay", W. S. Harmon, filed June 17, 1980), now abandoned. Such description is hereby incorporated by reference. Also, at least part of the invention disclosed in the forementioned application was reduced to practice before the conception of the present invention.
The forementioned application claims various embodiments of an improved woven geotextile suitable for use immediately under a pavement overlay. Broadly, that improved geotextile comprises a porous cap coated woven tape fabric having a shrinkage force of less than 30 gm/inch at 300.degree. F. at constant length in both warp and weft directions. The product permits reduction of both "reflective cracking" and "thermal construction cracking" in repaired roads.
U.S. Pat. No. 3,443,541 (Chopra) discloses tape interwoven with a bulky yarn for use as a carpet backing.
Also, U.S. Pat. No. 3,400,004 (Corry) discloses stretchable bulky yarns interwoven with unbulked yarns as a precursor for coated fabrics, particularly in the upholstery field.
None of the known prior art discloses any geotextile comprising a woven bulked yarn.